Synthesis And Electrochemical Properties Of The Novel Aluminum Battery Cathode

Aluminum battery possesses high theoretical energy capacity?2980mAh/g,8063mAh/cm³?,benefitting from its three-electron-redox properties.In addition,the aluminum battery has good security,low flammability,low cost.Therefore the recently emerging aluminum batteries are considered as a proming new energy storage devices.Owing to the relatively weak ionic bond between S₂-and Al3+,which will promoting the Al3+ intercalation/de-intercalation the cathode materials,thus the transition metal sulfides are expected to be the excellent candidates for aluminum battery cathodes.In our work,a series of transition metal sulfide cathodes were synthesized by hydrothermal method.Under the optimal conditions,their morphologies,electrochemical performances were studied and the performance optimization model of the mechanism was established at last.The main contents are as follows:?1?Transition metal sulfide 3D Ni₃S₂ like-mountain nanostructure supported on the Ni foam are been constructed by in-situ synthesis method using Ni foam and thioacetamide as a raw materials.The influence of the electrochemical properties of the products aroused by the concentration of thioacetamide,reaction time and reaction temperature is studied in detail,respectively.And the optimum technological parameters of preparing the products are selected via conditional experiments.The results indicate that the products with high electrochemical capacity?236mAh/g?,high discharge voltage plateau?0.7eV?and favorable cycle stability?90 cycles?under the optimum technological parameters?the concentration of thioacetamide: 0.33mMol/L,reaction temperature: 150 oC,reaction time: 15h?.Moreover,experimental measurements and the first-principles DFT computations were conducted to determine the charge/discharge reaction mechanism,which is Al3+ insert/exsert into Ni₃S₂ cathode forming Alx Ni₃S₂ solid solution during the discharge/charge process.?2?Petals-like structured MoS₂ with excellent electrochemical performance were synthesized by hydrothermal method using sodium molybdate and thioacetamide as a raw materials.The effect of different reaction conditions such as temperature,reaction time on the product morphology and the electrochemical properties were studied in detail,respectively.And the optimum technological parameters of preparing the products are selected via conditional experiments.The results indicate that the products deliver an initial high capacity of 127.8mAh/g and the discharge capacity remain 44.4mAh/g after 50 cycles,and with excellent coulomb efficiency at 110% under the optimum technological parameters?reaction temperature: 200 oC,reaction time: 28h?.Moreover,based on the electrochemical reaction equation and the electrochemical reaction diagram,the charge/discharge reaction mechanism of MoS₂ cathode is put forward.?3?The cobalt chloride hexahydrate was used as cobalt source,the thiocarbamide was used as sulfur source and the ultrapure water,ethylene glycol was used as solvent.The conditions such as temperature,reaction time on the product morphology and the electrochemical properties were studied in detail,respectively.And the optimum technological parameters of preparing the products are selected via conditional experiments.The results indicate that the products with high electrochemical capacity?179.2mAh/g?,high discharge voltage plateau?0.55eV?and favorable cycle stability?50 cycles?under the optimum technological parameters?reaction temperature: 150 oC,reaction time: 15h?.Moreover,based on the electrochemical reaction,the charge/discharge reaction mechanism of CoS cathode is put forward.